From 3af02584c1f9745597b84ea17c0f15279fdc105c Mon Sep 17 00:00:00 2001
From: Michael Chirico <chiricom@google.com>
Date: Sat, 2 Jul 2022 04:37:53 -0700
Subject: [PATCH] error early if missing DiagrammeR (#8037)

---
 R-package/R/xgb.plot.multi.trees.R | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/R-package/R/xgb.plot.multi.trees.R b/R-package/R/xgb.plot.multi.trees.R
index 063f1034a..fc54d777d 100644
--- a/R-package/R/xgb.plot.multi.trees.R
+++ b/R-package/R/xgb.plot.multi.trees.R
@@ -62,6 +62,9 @@
 #' @export
 xgb.plot.multi.trees <- function(model, feature_names = NULL, features_keep = 5, plot_width = NULL, plot_height = NULL,
                                  render = TRUE, ...){
+  if (!requireNamespace("DiagrammeR", quietly = TRUE)) {
+    stop("DiagrammeR is required for xgb.plot.multi.trees")
+  }
   check.deprecation(...)
   tree.matrix <- xgb.model.dt.tree(feature_names = feature_names, model = model)